Level indicators are used for monitoring the liquid level in a container, e.g. in a tank of a vehicle. The tank may for example be adapted to hold fuel to be used by the vehicle engine for providing propulsion. Naturally, it is important for the driver of the vehicle to be able to monitor the amount of fuel left in the tank. This of course also applies to other tanks holding liquid of the vehicle.
A commonly used level indicator for vehicles comprises a float and a potentiometer. As the level of liquid changes in the tank, the float moves a contact along the resistor of the potentiometer, thereby e.g. increasing the resistance of the potentiometer. The change in resistance is used to indicate an altered level of liquid in the tank. This type of level indicator comprises interconnected moving mechanical parts that are easily worn and may e.g. get stuck in one position, and also limits the accuracy of the level indicator. Furthermore, the components of this level indicator must be placed inside the tank.
Another approach for a level indicator is described in US2010/0269586. In US2010/0269586 a float is arranged inside a solenoid coil which in turn is arranged inside the tank. The solenoid is wound so that it has a varying inductance along its axial length. The float changes the overall inductance of the solenoid as it moves along the length of the solenoid. Thus, a change in inductance is used for indicating the level of liquid. The level indicator including the solenoid and the float and other necessary components (e.g. cables) must be placed inside the tank, thus reducing the amount of liquid that can be stored in the tank and may also pose a potential fire hazard if the tank stores e.g., fuel, since the electrical components must be placed inside the tank.
Accordingly, there is room for improvements in the presently known level indicators.